Couch assembly for papermaking machines



Aug. M, 1966 J. P. BREZINSKH 3,265,976

COUCH ASSEMBLY FOR PAPERMAKING MACHINES Filed Sept. 1.2, 1965 A TTO NE YS' United States Patent C) 3,266,976 COUCH ASSEMBLY FOR PAPERMAKING MACHINES Jerome I. Brezinslri, Beloit, Wis., assignor to Beloit Corporation, Beloit, Wis., a corporation of Wisconsin Filed Sept. 12, 1963, Ser. No. 308,490 4 Claims. (Cl. 162-314) The present invention relates .to an improvement in devices for removing liquid from liquid-containing web material, and more particularly, to an improved couch assembly for use in paper making machinery.

Although the instant invention may have a number of uses in different elds, it is used to particular advantage in the art of paper making and will be described primarily in connection therewith. In the Fourdrinier-type paper making machine the stock or dilute suspension of fibers is fed onto a traveling forming wire at one end of a generally planar reach and as the wire moves forward (Le. longitudinally) water passes through the wire and the fibers retained on the upper surface of the wire form what is generally referred to in the art as a moist paper web. As this moist paper web moves forward further on the forming wire, further dewatering thereof is usually carried out next with the so-called suction boxes, which are devices for creating subatmospheric pressure beneath the forming wire and thereby causing a pressure differential across the moist web on the forming wire to effect dewatering of the moist web. Next, the web traveling on the forming wire reaches what is known as the couch roll, which is the roll supporting the wire at the longitudinal end of the upper reach on which the web has been formed and partially dewatered. Often a turning roll is employed in conjunction with -the couch roll and the forming wire it- Aself will be reversed in direction at the turning roll. There will then be a wire reach between the couch roll and the turning roll which is generally downwardly inclined and the moist web is usually taken from the forming wire along this downwardly inclined reach of the wire between the couch roll and the turning roll. From there the moist web goes through a press section where it is dewatered primarily by the use of mechanical pressure prior to the dryer section where the water is removed from the web to the extent desired by the use of heat (which is generally more expensive than mechanical pressure, hence mechanical pressure is used first in the press section to remove a great bulk of the water).

As the traveling moist web on the forming wire passes over the couch roll, prior art workers have attempted to effect additional dewatering of the web. This has been done by the use of a so-called suction couch roll, which is a rotary perforate shell that is equipped with an interior suction gland which creates a subatmospheric pressure along a suction area extending for -the cross-machine width of the couch roll along the underside of the wire wrapping the couch roll. It will be appreciated that the moist web is in a very delicate condition as it passes over the couch roll and the function of the suction couch roll is to create a limited pressure differential across the plane of the web (ie. generally tangential to the couch roll) by the use of ambient atmospheric pressure exposed to the top side of the web and subatmospheric pressure in the suction area beneath the wire. This application of a pressure differential tends to cause a limited amount of dewatering of the web during which the water moves generally normal to the plane of the web.

Suction couch rolls are, however, very expensive devices and the amount of dewatering that can be accomplished using a suction couch roll is, of course, limited to the pressure differential which this device can actually create, which in turn is limited by the fact that ambient 3,266,976 Patented August 16, 1966 atmospheric pressure minus whatever minimum absolute pressure might be generated in the suction area will constitute the maximum so-called pressing force.

It will also be appreciated that the action of the suction couch roll often tends to cause an undesirable stapling of some of the fibers of the web onto the forming wire, in that the fibers may become unduly wrapped about the strands of the forming wire itself. In addition to the possibility of this stapling effect, it will be appreciated that water continues to follow the web along the underside of the wire at the off-running side of the couch roll and along the wire reach between the couch roll and the turning roll. The web is still very moist under these conditions and there is a tendency for a water film to remain on the underside of the wire reach between .the couch roll and the turning roll.

The removal of the web from the wire is thus complicated not only by the possibility of the stapling effect previously mentioned but also by the actual existence of the water iilm on the underside of the wire reach. This water film tends to impart to the wire the properties of a solid sheet rather than a porous material through which air might ow freely as the web is removed from the wire reach; and in this respect, it will be appreciated that this water film may have a tendency to impair the best operating conditions for actual removal of the moist web from the wire reach.

In the instant invention, however, the dewatering of the web at the couch station is accomplished by the use, preferably in combination, of a plurality of separate and distinct functions. One of these dewatering concepts or functions involves lthe provision of a highly waterabsorptive felt material positioned intermediate the wire and the couch roll at the couch station so as to readily receive water from the web, through the forming wire and into the body of' such felt at the couch station. It will be appreciated that this felt will have the additional function of receiving water from the underside of the wire at the immediate off-running side of the couch station so that it will tendto remove the previously described film of water tending to underlie the downrunning wire reach. In addition, it will be appreciated that the forming wire itself is underrtension and will press on the felt wrapping the couch roll at :the couch station and the felt will tend to reduce or completely eliminate the previously mentioned stapling effect in that the body of the felt itself will tend to fill the interstices in the forming wire in such a manner that the felt may still receive water but the fibers of the web will not be drawn into such interstices. Also, after the wire and felt have passed the so-called pressure zone of .the couch station, the felt itself will expand briefly from its compressed condition and will tend to lift the web slightly out of the interstices of the forming wire; and this condition is particularly important when a lumpbreaker roll or comparable roll is used to apply a certain amount of pressure to the topside of the web at the couch station. In connection with the use of the felt, it will be appreciated that the felt is an endless loop traveling not only through `the couch station but through a second station at which it is dewatered by mechanical pressure so as to be prepared again in a highly water-absorptive condition for passing through the previously-mentioned couch station.

Still another function which is contemplated in the practice of the instant invention for purposes of dewatering at the couch station involves the concept of using a pressure roller in the position heretofore used for the so-called lumpbreaker roll. The lumpbreaker roll used in the prior art did not actually apply any significant kpressure to the top surface of the roll. The essential function of the lumpbreaker roll was to avoid the formation of excessively large fiber clusters or bundles in the moist web, and to generally function to smooth the moist web in the relatively mobile condition of the web at the couch station.

In the practice of the instant invention, however, a roll presenting a solid surface or even a very closely woven wire surface capable of applying a certain amount of pressure to the moist web may be used in the position of the lumpbreaker roll so as to dene a mechanical press nip with the couch roll. The couch roll is, however, unique also in its preferred structure in that it is provided with a plurality of alternating very closely spaced land and grooves generally circumferentially aligned, with the grooves being of such structure and depth that they function as vents to ambient atmosphere at the couch station. This permits the application of pressure to the aforesaid solid-surfaced roll (.e. solid-surfaced lumpbreaker roll) to the extent that water may be forced mechanically out of the moist web at the couch station along a plane generally normal to the plane of the web at such nip (i.e. which plane of water travel may be considered to be substantially lthe plane defined by the centroidal axes of the couch roll and the aforesaid solid lumpbreaker pressure roller).

It must be appreciated that an important concept of the instant invention involves the concept of water movement in this plane generally perpendicular to the plane of the web, as contrasted to Water movement in the plane of the web. Actually, the web is moving through a slight arc as it passes over the couch station, but it also moves into a plane of the common tangent to the lumpbreaker and couch roll when it passes through what must be considered the line of the nip load. In this socalled tangent plane, water movement in the web, if it is signicant in character, will cause a disruption of the web and damage thereto which in the language of the art is referred to as crushing Possibly in its simplest form, crushing is apparent at conventional press nips in the press section when the water load at the press nip is so great that there is actually developed a ow of water in the plane of the web entering the nip, opposite to the direction of movement of the web. This type of crushing is manifested by the buildup of a puddle of water at the oncoming side of the nip. The term crushing is, however, a term that is peculiar in meaning to those skilled in the art and actually refers to what constitutes incipient fracture in the web itself. The formation of the so-called puddle of water at the nip is merely suggestive of evidence of crushing. Crushing itself involves a disrupting effect in the web which is caused by an undesirable ilow (usually merely an excessive flow) of water in the plane of the web, which for practical purposes is substantially the plane of the common tangent between nip-defining rolls. The desirable type of ow in the web during a pressing action is a flow that is substantially perpendicular to the plane of the web, which thus is a flow which might be expressed in terms of the nip load line as a flow that is in a plane that is generally perpendicular to the plane of the web and passes through the nip load line.

As previously indicated, the undesirable crushing effect is obtained by undesirable, excessive flow of water in the plane of the web and it will be appreciated that this undesirable ow of water may take place not only in Ithe longitudinal direction of web movement but also in the cross-machine direction. The instant invention affords a unique couch roll structure which avoids such undesirable flow in either direction, to the extent that the flow rate of water in and through the web at the couch station is not suflicient to cause a crushing effect. This means that there is no undesirable buildup of excessive pressure gradients in the plane of the web at the couch station of the invention. l v

It is thus an object of t-he instant invention to provide an improved dewatering of the web at the couch station, and an improved couch assembly for such purpose.

It is a further object of the instant invention to provide an improved method of dewatering the web at the couch station without the creati-on of undesirable pressure gradients in the plane of the web at such station.

Othe-r and further objects, features and -advantages of the present invention will become apparent to those skilled in the lart from the following detailed disclosure thereof and the drawings attached hereto and made a part hereof.

As shown on the drawings:

FIGURE l is an essentially diagrammatic side elevation view of a couch station of the invention and functioning elements in the immediate vicinity thereof;

FIGURE 2 is a detail fragmentary sectional view taken generally along the line II-II of FIGURE l;

FIGURE 3 is a detail fragmentary sectional view taken generally along t-he line III-III of FIGURE l, and comparable in many respects to the view of FIGURE 2; and

FIGURE 3A is a fragmentary detail view taken generally from the encircled portion of FIGURE 3 designated 3A.

On the drawings:

Referring to FIGURE 1, it will be seen that the couch assembly of FIGURE 1 includes the force of the looped forming wire F in the region of the couch station, carrying on the top surface thereof a moist web W traveling over conventional suction boxes indicated diagrammatically at 11a through 11e. Next, the forming wire F with the moist web W thereon travels around a couch roll 12 embodying the invention but placed in the location of a conventional couch roll and defining generally a couch station S-1, which is essentially the location coincident with the peripheral portion of the couch roll 12 that is wrapped by the forming wire F. The forming wire F then travels downwardly through a forming wire reach FR to a conventional turning roll 13 dening the turning roll station S-2 at which the direction of the forming wire F is substantially reversed and the forming wire F then returns in .the direction indicated by the arrowheads traveling around conventional return rolls 14 :and I15. Generally speaking, means are provided such as a felt wrapped suction pickup roll (not shown) or other devices which will remove the web W from the forming wire reach FR between the couch station S-1 and the turning roll station S42, but such means for removing the web W from the forming wire F are not in and of themselves a part of this invention and such means are thus not described in detail in FIGURE 1 and the web W is merely indicated las separating from the forming wire `reach FR.

Although it will be noted that a pressure roller 16 is shown in FIGURE 1 at approximately the location of a conventional lumpbreaker roller of the prior art, it will be appreciated that in connection with one aspect of the invention, a lump'breaker roll can be employed in the position of the pressure roller 16 at the couch station S-l. In the preferred embodiment of the invention, however, a pressure roller 16 is employed in the position indicated and its function will be described in greater detail hereinafter.

One important aspect of the instant invention, however, involves the use of a relatively heavy looped felt 17 to wrap the couch r-oll 12 at the couch station S-1, such that the felt 1'7 is interposed between the forming wire F and the couch roll 12 at the couch station S1. The felt 17 in this particular arrangement is capable of several different particularly useful functions. One of these is that of merely absorbing water from the web W through the forming wire F and this is accomplished primarily by passing the felt through a felt only press nip N-1 that is defined by the couch roll 12 within the lop of the felt 17 and a press-ure roll 18 outside the loop of the felt '17, but within the loop of the forming wire F.

The pressure roll 18 is here shown in its preferred position directly beneath the couch Iroll 12. The felt 17 is mounted on a plurality of felt guide and tensioning rollers `17a through 17k, which are shown herein in essentially dia-grammatic arrangement to provide for the selection of suliicient room for a full felt run in a relatively protected Iarea beneath the suction boxes 11a, etc. which substantially prevent wetting of the felt 17 by water from the wire F. Preferably Ialso a saveall device 19 is mounted in association with the last suction box 113 to provide some additional protection for the felt f17 as it passes lover the g-uide roll 17] and approaching the couch station S-1. In this manner the felt 17 is dewatered to the extent desired in the felt only press nip N-l and is then fed back into the couch station S41 in such dewatered, highly absorbent condition so that it is capable of receiving water from the web W at t-he couch station S-1.

At the off-running side of t-he couch station S1 (beneath the forming wire reach FR) the felt '17 is separated from the forming wire F and the surface of the couch roll 12 by means of a felt guide roll 17k. Before such separation can occur, however, the felt 117 expands (i.e. to assist in lifting the web W off the wire reach FR) and absorbs water that norm-ally tends to form a film on the underside of the Wire reach FR. A saveall 21 is interposed at the off-running side of the couch station S-1 between the felt 17 and the surface of the couch roll 12 so -as to minimize undesirable water movement from the felt 17 to the couch roll 12 or vice versa once these elements are separated fat the off-running side of the couch station S-l.

The felt 17 is here shown reversing its direction su-bstantially around the felt guide roll 17k and then traveling in a generally horizontal direction from the felt guide troll 17k to the felt roll 17j in a plane T-T (shown as the common tangent at nip N-I in FIGURE 1 and Vin cross machine direction in FIGURE 3) generally tangential to the couch roll 12 and the pressure roller 18. One and preferably both of the couch roll 12 and pressure roll 18 'are grooved rolls, having7 a runique groove and land structure which will be described in detail hereinafter. Essentially the groove and land structure is that of alternating generally circuniferentially aligned closely (axially) spaced lands and grooves.

As indicated in FIGURE 3, in the preferred embodiment of the invention, the couch roll indicated only fragmentarily at I2 is defined lby a ductile iron shell 12x which is mounted on known anti-deflection mounting means for pressure rollers. Such anti-deflection mounting means are shown in U.S. Patent No. 2,648,122; 2,651,103; and 2,651,241; and in addition, in U.S. application Serial No. 102,571, filed April 12, 1961, now Patent No. 3,097,590 and Serial No. 154,804, led November 24, 1961, in the name of Edgar J. Justus. The antideection mounting means preferred and used herein are those involving the use of rubber sandwiches on a through shaft as shown in Justus application Serial No. 102,571, and since the specific aspects of the anti-deflection roll mountings are not a part of this invention, such anti-deflection roll mounting means are not shown in connection with the couch roll 12 and such anti-deflection roll mounting means are indicated in combination with known fluid actuated moving and pressure loading means, by the diagrammatic showing of double-headed arrows centered on the rolls 16 and 18.

As indicated in FIGURE 3, the roll 18 is also provided with a ductile iron shell 18x. The roll 18 is further provided with a solid elastomer or resilient (i.e. rubber) cover designated generally 22 in FIGURE 3 and shown in greater detail in FIGURE 3A, in the absence of section lines for purposes of simplifying the description of specific aspects thereof. In this respect, it should be noted that the couch roll 12 is likewise provided with a cover designated generally 12a in FIGURE 3 and 12a in FIGURE 2, which is preferably a stainless steel cover mounted on the ductile iron shell 12x for superior wear and this stainless steel cover 12a is provided with a plurality of generally circumferentially aligned closely axially spaced lands 12b, 12b and grooves 120, 12e. It will further 'be noted that in FIGURE 2 the encircled portion designated IIA shows a structure which involves the a1- ternating lands 12b and grooves 12C in a relationship substantially identical to that of the lands 22b and grooves 22C shown in greater detail in FIGURE 3A.

The specic features of the preferred grooved roll structure shown in FIGURE 3A are described in considerable detail in the previously filed applications yof Edgar J. Justus, Serial No. 258,391 (FIGURE 5B thereof) filed February 14, 1963, now abandoned and in subsequently filed application entitled Improved Press Roll Assemblies (A), Serial No. 302,423, filed August 15, 1963, now Patent No. 3,198,696, bioth of which applications are made a part hereof and included herein by reference. Also, it will be noted that the doctors d and wipers w indicated diagrammatically in FIGURE 1 of the instant application, are the elements previously described in said earlier led applications.

For purposes of preferred operation in the practice of the instant invention, however, the land axial dimensions 27 -are preferably within the range of about 0.05 inch to 0.15 inch, and preferably about 0.1 inch; the groove depths 28 may range from approximately 0.05 inch to as much as 1A inch in the case of excessive amounts of water, and are preferably about 1A; inch; and the relationship of the groove cross-sectional area to the groove mouth dimension 26 should be at least about twice the square of the groove mouth dimension (in cross-sectional area) and is preferably five to ten times the square of the groove mouth in cross-sectional area in order to carry the flow of water without any buildup of pressure gradient. It will be appreciated that the grooves vent to ambient atmosphere, but because of the excessive amount of water particularly at the couch station, it will be appreciated that water may actually flow freely directly normal to the web into the grooves and then circumferentially in the grooves to a rather substantial extent (ie. even to the extent of substantially lling the grooves so long as the groove capacity is sufficient to prevent the desired venting effect which merely involves the elimination of any back pressure or resistance in water flow away from the couch station in the grooves).

The roll 16 shown in the position of the lump-breaker lroll is preferably merely a solid-surfaced roll which is provided with conventional fluid pressure actuated means for positioning and delicate pressure control so that it may be used to apply a certain amount of pressure at the couch station S-l, to the extent desired. If the couch roll itself is to be stainless steel clad, then the roll 16 in the position of the lumpbreaker roll would preferably have a solid elastomer cover. A relatively light nip load is applied, but the problem of stapling the web to the wire is avoided because of the' felt expanding at the off-running side of the couch station S-l.

I claim as my invention:

y1. In a machine for forming a wet brous web on a looped traveling forming wire, in combination, a looped traveling felt within the wire loop, a couch roll within the felt loop, a turning roll outside the felt loop and within the wire loop mounting with said couch roll a reach of said wire extending therebetween from a couch station to a turning station, a pressure roll outside the felt loop and within the wire loop defining with said couch roll a felt only press nip for receiving and dewatering said felt, and guide means for separating the felt from the couch roll and said Wire reach at the immediate off-running side of said couch station and then passing the felt through said felt only nip so as to maintain the felt Vseparate from said rolls at substantially the immediate oncoming and offrunning sides of said nip, at least one of said couch and pressure rolls -being a gr-ooved roll presenting to the felt at the nip a peripheral surface portion having a plurality of alternating generally circumferentially aligned grooves and ridges, said ridges presenting to such felt smooth generally continuously cylindrical closely axially spaced land areas for supporting the felt and permitting the felt to bridge the grooves, ysaid grooves being vented to ambient atmosphere to facilitate reception of water at the nip.

2. In a machine for forming a wet fibrous web on a looped traveling forming wire, in combination, a looped traveling felt within the wire loop, a couch roll within the felt loop, a turning roll outside the felt loop and within the wire loop mounting with :said couch -roll a reach of said wire extending therebetween from a couch station to a turning station, a pressure roll outside the felt loop and within the wire loop defining with said couch roll a felt only press nip for receiving and dewatering said felt, guide means for separating the felt from the couch -r-oll and said wire reach at the immediate off-running side f said couch station and then passing the felt through said felt -only nip so as to maintain the felt separate from said rolls at substantially the immediate oncoming and offrunning sides of said nip, and means associated with said couch and pressure `rolls remote from the felt only nip for receiving water from the surface of said rolls, at least one of said couch and pressure rolls being a grooved roll presenting to the felt at the nip a peripheral surface portion having a plurality of alternating generally circumferentially aligned grooves and ridges, said -ridges presenting to such felt smooth generally continuously cylindrical closely axially spaced land areas for supporting the felt and permitting the felt to bridge the grooves, said grooves .being vented to ambient atmosphere to facilitate reception of water at the nip.

3. In a machine for forming a wet fibrous web on a looped traveling forming wire, in combination, a looped traveling felt within the wire loop, a couch roll within the felt loop, a turning roll outside the felt loop and within the wire loop mounting with said couch roll a reach of said Wire extending therebetween from a couch station t0 a turning station, a lump-breaker roll in nip-defining relationshp with said couch roll at said couch station to assist in transfer of water from the web to the felt at such couch station, a pressure roll loutside the felt loop and Within the wire loop defining with said couch roll a felt only press nip for receiving and dewatering said felt, and guide means for separating the felt from the couch roll and said wire reach at the immediate off-running side of said e0 couch station and then passing the -felt through said felt only nip so as to maintain the felt sepa-rate from said rolls at substantially the immediate oncoming and offrunning sides of said nip, at least one of said couch and pressure rolls being a grooved roll presenting tothe felt at the nip a peripheral surface portion having a plurality of alternating generally circumferentially aligned grooves and ridges, saidv ridges presenting to such felt smooth generally continuously cylindrical closely axially spaced land areas for supporting the felt and -permitting the felt to bridge the grooves, said grooves being vented to ambient atmosphere to facilitate reception of water at the nip.

4. In a machine for forming a wet fibrous web on a looped traveling forming wire, in combination, a looped 10 traveling felt within the wire loop, a couch roll within the felt loop, a turning roll outside the felt loop and within the wire loop mounting with said couch roll a reach of said wire extending therebetween from a couch station to a turning station, a lump-breaker roll in nip-defining relationship with said couch roll at said couch station to assist in transfer of water from the web to the felt at such couch station, a pressure roll outside the felt loop and within the wire loop defining with said couch roll a felt only press nip for receiving and dewatering said felt, guide means for separating the felt from the couch roll and said wire reach at the immediate off-running side of said couch station and then passing the felt through said felt only nip so as to maintain the lfelt separate from said rolls at substantially the immediate oncoming and off-running sides of said nip, and means associated with said couch and pressure rolls remote from the felt only nip for receiving water from the surface of said rolls, at least one of said couch and pressure rolls being a grooved roll presenting to the felt at the nip a peripheral surface por- 3 tion having a plurality of alternating generally circumferentially aligned grooves and ridges, said ridges presenting to such felt smooth generally continuously cylindrical closely axially spaced land areas for supporting the felt and permitting the felt to bridge the grooves, said grooves being vented to ambient atmosphere to facilitate reception of water at the nip.

References Cited by the Examiner UNTTED STATES PATENTS 1,483,562 2/1924 wagner 162-358 1,514,011 11/1924 Pope 162-349 2,550,774 5/1951 Clem 162-314 2,858,747 11/1958 wagner 162-361 2,888,074 5/1959 Hornbostel 162-306 2,947,356 8/1960 Hombestei 162-314 FOREIGN PATENTS 415,349 6/1925 Germany.

r OTHER REFERENCES The Paper Industry, August 1943, p. 530. known as Paper Industry and Paper World.)

S. LEON BASHORE, Primary Examiner.

I. H. NEWSOME, Assistant Examiner.

(Also 

1. IN A MACHINE FOR FORMING A WET FIBROUS WEB ON A LOOPED TRAVELING FORMING WIRE, IN COMBINATION, A LOOPED TRAVELING FELT WITHIN THE WIRE LOOP, A COUCH ROLL WITHIN THE FELT LOOP, A TURNING ROLL OUTSIDE THE FELT LOOP AND WITHIN THE WIRE LOOP MOUNTING WITH SAID COUCH ROLL A REACH OF SAID WIRE EXTENDING THEREBETWEEN FROM A COUCH STATION TO A TURNING STATION, A PRESSURE ROLL OUTSIDE THE FELT LOOP AND WITHIN THE WIRE LOOP DEFININF WITH SAID COUCH ROLL A FELT ONLY PRESS NIP FOR RECEIVING AND DEWATERING SAID FELT, AND GUIDE MEANS FOR SEPARATION THE FELT FROM THE COUCH ROLL AND SAID WIRE REACGH AT THE IMMEDIATE OF-RUNNING SIDE OF SAID COUCH STATION AND THEN PASSING THE FELT THROUGH SAID FELT ONLY NIP SO AS TO MAINTAIN THE RELT SEPARATE FROM SAID ROLLS AT SUBSTANTIALLY THE IMMEDIATE ONCOMING AND OFFRUNNING SIDES OF SAID NIP, AT LEAST ONE OF SAID COACH AND PRESSURE ROLLS BEIN A GROOVED ROLL PRESENTING TO THE FELT AT THE NIP A PERIPHERAL SURFACE PORTION HAVING A PLURALITY OF ALTERNATING GENERALLY CIRCUMFERENTIALLY ALIGNED GROOVES AND RIDGES, SAID RIDGES PRESENTING TO SUCH FELT SMOOTH GENERALLY CONTINUOUSLY CYLINDRICAL CLOSELY AXIALLY SPACED LAND AREAS FOR SUPPORTING THE FELT AND PERMITTING THE FELT TO BRIDGE THE GROOVES, SAID GROOVES BEING VENTED TO AMBIENT ATMOSPHERE TO FACILITATE RECEPTION OF WATER AT THE NIP. 